[clang] [llvm] [AMDGPU][Clang] add __builtin_amdgcn_av_(load|store)_b128 (PR #199176)

[Sameer Sahasrabuddhe via cfe-commits]

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@@ -5754,6 +5756,32 @@ returns the bit at the position of the current lane. It is almost equivalent to
 ``(mask & (1 << lane_id)) != 0``, except that its behavior is only defined if
 the given mask has the same value for all active lanes of the current wave.
 
+
+__builtin_amdgcn_av_{load,store}_b128
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ssahasra wrote:

Done.

https://github.com/llvm/llvm-project/pull/199176